51513821 has 8 divisors (see below), whose sum is σ = 52517760. Its totient is φ = 50516928.

The previous prime is 51513811. The next prime is 51513841. The reversal of 51513821 is 12831515.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-51513821 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51513811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14405 + ... + 17621.

It is an arithmetic number, because the mean of its divisors is an integer number (6564720).

Almost surely, 2^51513821 is an apocalyptic number.

It is an amenable number.

51513821 is a deficient number, since it is larger than the sum of its proper divisors (1003939).

51513821 is a wasteful number, since it uses less digits than its factorization.

51513821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3523.

The product of its digits is 1200, while the sum is 26.

The square root of 51513821 is about 7177.3129373046. The cubic root of 51513821 is about 372.0842223647.

The spelling of 51513821 in words is "fifty-one million, five hundred thirteen thousand, eight hundred twenty-one".